Composites are well known dental restorative materials on the market. However most of the organic based dental restoratives to date are based on methacrylate and/or acrylate chemistry. The newer materials based on oxirane chemistry presume lower polymerization shrinkage and lower stress.
WO 98/47046 describes a photocurable, addition polymerizable composition which contains an epoxy resin and a photoinitiator system. The epoxy resin include glycidyl ether monomers.
WO 00/19967 discloses a dental composition useful for making dental prostheses or dental restorations comprising a silicone oligomer or polymer. The compositions possess epoxy-reactive groups and are polymerizable via a cationic cure process.
WO 98/22521 describes polymerizable substances containing an epoxide or a mixture of epoxides, a filler material, initiators, inhibitors and/or accelerators. The substances include cycloaliphatic epoxy functions with a relatively high viscosity.
WO 01/51540 discloses polymerizable compositions based on epoxies that contain silicon. The compositions are based on silane compounds with cycloaliphatic epoxy functional groups. These cycloaliphatic epoxy-functional group-containing compounds have a relatively high viscosity. This leads on the one hand to inferior handling properties and to poor mechanical properties because a reduced amount of filler must be used to prepare the dental compositions.
A disadvantage of the dental composites on the market is that the epoxy-functional polymerizable resins do not possess refractive indices similar to these of the fillers commonly used to prepare dental composites. This results in an increased opacity of the composite which leads to poor esthetic properties in the cured material. A further drawback of some of the epoxy-functional dental composite materials on the market is that they contain components that are not hydrolytically very stable and can decompose in the mouth over the years releasing undesirable substances.
It is thus an object of the present invention to alleviate one or more of the problems mentioned above.
It is another object of the present invention to provide a composition with improved properties, especially to provide an esthetic composition for use in the dental field.
It is a further object of the present invention to provide a composition wherein the refractive index of the curable resin is similar to the refractive index of the used fillers.